Some examples of progress for my project to bring in a chunk of sea ice data representing ~90W-0W and north of 90S from NSIDC sea ice concentration data. 

In the first plot, the data remain in native projection and are mapped with coastlines, a location of a field site of interest, and a contour identifying 50% SIC.  The second plot uses the same data, but is projected to standard lat-long coordinates for analysis of nearest distance between the field site and the contour. That location is identified by the blue square. (I'm not really interested in closest points that require traversing mountain ranges, so still some work to do to mask locations that make no sense.)

I can't find my post for homework on day 2, but there were several sea ice data sets that could be useful in the PolarWatch catalog (NSIDC, OSAIFl, even the sea_ice_fraction mask provided with the MURSST data), but the length of the time series (since 1978), the resolution of data (25km), and the time step options (monthly and daily) are all suitable for use here. For developing an index, I chose the the monthly data.